Recent studies have identified that hyperglycemia induces de novo diacylglycerol (DAG) synthesis and activates Protein Kinase C (PKC), which leads to many kinds of vascular abnormalities involving abnormalities of the retina, glomeruli and cardiovascular tissues. In clinical assessment, measurement of PKC activity in vascular tissues is desired, but it is not easy to obtain vascular samples from diabetic patients repeatedly.
The inventor has discovered that PKC activity, e.g., PKCxcex2 activity, in mononuclear cells, e.g., monocytes, correlates with PKC activity in other tissues, e.g., in vascular or cardiovascular tissue (e.g., in retinal, kidney or aorta vascular tissues or heart). Accordingly, the invention features a method of evaluating the level of PKC activity in a tissue other than monocytes of a subject, e.g., in vascular or cardiovascular tissue, e.g., in retinal, kidney or aorta vascular tissues or heart. The method includes evaluating the level of the PKC activity, e.g., PKC xcex2 activity, in mononuclear cells, e.g., monocytes, of the subject. The level of PKC activity in mononuclear cells is correlated with the level of PKC activity in other tissues, e.g., vascular tissue, e.g., in retinal, kidney or aorta vascular tissue or in heart. The subject can be a human, or any non-human animal, e.g., a non-human mammal, e.g., rodent, e.g., a mouse or a rat.
In a preferred embodiment, PKCxcex2 activity is evaluated.
In a preferred embodiment, the subject is a human.
In a preferred embodiment, the subject is an experimental animal.
The invention also features methods of evaluating a subject, e.g., staging of, evaluating the treatment of, or determining if a subject is at risk for (e.g., has a genetic disposition to), has a symptom of, or is afflicted with, a PKC related disorder, e.g., a disorder described herein, e.g., diabetes, diabetes mellitus, Type I diabetes, Type II diabetes, diabetic retinopathy, proliferative diabetic retinopathy, non-proliferative diabetic retinopathy, diabetic nephropathy, microalbumiuria, proteinuria, renal failure, cardiovascular disorder, hypertension, atherosclerosis, coronary artery spasm, congestive heart failure, coronary artery disease, valvular disease, arrhythmias, cardiomyopathy, aging, or an aging-related disorder. The method includes evaluating the level of PKC activity, e.g., PKC xcex2 activity, in mononuclear cells, e.g., monocytes, of the subject. Optionally, the method also includes comparing the level of the PKC activity in monocytes of the subject with a standard, e.g., the level of PKC activity in a control sample, e.g., a non-diabetic subject, a preset value, or a basal activity value.
In some embodiments, the level of the PKC activity in monocytes of a subject correlates with risk of developing a PKC-related disorder, e.g., diabetic retinopathy or another PKC related disorder described herein. For example, the level of PKC activity in monocytes of a subject correlates with a genetic predisposition to a PKC-related disorder, e.g., retinopathy.
In a preferred embodiment, PKCxcex2 activity is evaluated.
In a preferred embodiment, the subject is a human.
In a preferred embodiment, the subject is an experimental animal.
In another aspect, the invention features a method of evaluating a subject for the extent, stage, or severity, of a PKC related disorder, e.g., a disorder described herein, e.g., diabetes, diabetes mellitus, Type I diabetes, Type II diabetes, diabetic retinopathy, proliferative diabetic retinopathy, non-proliferative diabetic retinopathy, diabetic nephropathy, microalbumiuria, proteinuria, renal failure, cardiovascular disorder, hypertension, atherosclerosis, coronary artery spasm, congestive heart failure, coronary artery disease, valvular disease, arrhythmias, cardiomyopathy, aging, or an aging-related disorder. The method includes evaluating the level of PKC activity in monocytes of the subject and, optionally, comparing the level of the PKC activity in monocytes of the subject with a standard, e.g., a preset value, the level of PKC activity in a control sample or subject, or a basal activity value. The level of PKC activity in the monocytes is correlated, preferably positively, with the extent, stage, or severity, of the PKC related disorder.
In a preferred embodiment, PKCxcex2 activity is evaluated.
In a preferred embodiment, the subject is a human.
In a preferred embodiment, the subject is an experimental animal.
In another aspect, the invention features methods of evaluating the effect of a treatment for a PKC related disorder, e.g., diabetes, diabetes mellitus, Type I diabetes, Type II diabetes, diabetic retinopathy, proliferative diabetic retinopathy, non-proliferative diabetic retinopathy, diabetic nephropathy, microalbumiuria, proteinuria, renal failure, cardiovascular disorder, hypertension, atherosclerosis, coronary artery spasm, congestive heart failure, coronary artery disease, valvular disease, arrhythmias, cardiomyopathy, aging, or an aging-related disorder, which includes administering a treatment to a subject and measuring PKC activity, e.g., PKC xcex2 activity, in the subject""s mononuclear cells, e.g., monocytes. The treatment can be, e.g., administration of a compound, e.g., a protein (e.g., an antibody or a hormone, e.g., insulin), a small molecule, a vaccine, a nucleic acid). The subject can be a human, or a non-human animal, e.g., a rat or a mouse, or an animal model for a disorder described herein, e.g., a NOD mouse and its related strains, BB Rat, Leptin or Leptin Receptor mutant rodents, Zucker Diabetic Fatty (ZDF) Rat, Obese Spontaneously Hypertensive Rat (SHROB, Koletsky Rat), Wistar Fatty Rat, New Zealand Obese Mouse, NSY Mouse, Goto-Kakizaki Rat, OLETF Rat, JCR:LA-cp Rat, Neonatally Streptozotocin-Induced (n-STZ) Diabetic Rats, Sprague-Dawley rat, Rhesus Monkey, Psammomys obesus (fat sand rat), C57B1/6J Mouse. The level of PKC activity in the monocytes is correlated with the effect of the treatment. The method can be used, e.g., to evaluate the effect of an experimental treatment, e.g., an experimental compound, or a known treatment, e.g., insulin.
In a preferred embodiment, PKCxcex2 activity is evaluated.
In a preferred embodiment, the subject is a human.
In a preferred embodiment, the subject is an experimental animal.
In yet another aspect, the invention features a method of identifying a compound for treating a PKC related disorder, e.g., diabetes, diabetes mellitus, Type I diabetes, Type II diabetes, diabetic retinopathy, proliferative diabetic retinopathy, non-proliferative diabetic retinopathy, diabetic nephropathy, microalbumiuria, proteinuria, renal failure, cardiovascular disorder, hypertension, atherosclerosis, coronary artery spasm, congestive heart failure, coronary artery disease, valvular disease, arrhythmias, cardiomyopathy, aging, or an aging-related disorder. The method includes administering a test compound to a subject, e.g., an animal, e.g., a mouse or a rat, or an animal model for a disorder described herein, and measuring PKC activity, e.g., PKC xcex2 activity, in mononuclear cells, e.g., monocytes, of the subject. The level of PKC activity in the monocytes is correlated with the effect of the treatment. The method may also optionally include identifying a subject in need of a treatment for the PKC related disorder, and comparing the PKC activity, e.g., PKC xcex2 activity, in monocytes, after administration of a test compound, to a standard. A compound for the treatment of the disorder is identified when the PKC activity after the administration of the compound is altered, e.g., increased or decreased, as compared to a standard, e.g., a preset value, the level of PKC activity in a control sample, a basal activity value, or the PKC activity before, or in the absence of, the administration of the compound.
In a preferred embodiment, PKCxcex2 activity is evaluated.
In a preferred embodiment, the subject is a human.
In a preferred embodiment, the subject is an experimental animal.
In a preferred embodiment, the method further includes isolating a compound identified as having an effect on a PKC-related disorder, and, optionally, administering the compound to a subject, e.g., a human subject having such a disorder
In another aspect, the invention features a method of identifying a compound for the treatment of aging or an aging-related disorder in a subject, e.g., an animal. e.g., a mouse or a rat, or an animal model for a disorder described herein. The method includes administering a test compound to the subject and evaluating a PKC activity, e.g., a PKC xcex2 activity, in monocytes of the subject. The level of PKC activity is correlated with the effect of the treatment on the disorder. Preferably, the level of PKC activity is decreased compared to a standard. A compound for the treatment of aging or an aging-related disorder is identified when the PKC activity after the administration of the compound is altered, e.g., increased or decreased, as compared to a standard, e.g., a preset value, the level of PKC activity in a control sample, a basal activity value, or the PKC activity before, or in the absence of, the administration of the compound.
In a preferred embodiment, PKCxcex2 activity is evaluated.
In a preferred embodiment, the subject is a human.
In a preferred embodiment, the subject is an experimental animal.
In a preferred embodiment, the method further includes isolating a compound identified as having an effect on aging or an aging-related disorder, and, optionally, administering the compound to a subject, e.g., a human subject having such a disorder
In another embodiment, the invention provides a method of evaluating the effect of a treatment for aging or an aging-related disorder on a subject, which includes administering a treatment for aging or an aging-related disorder to a subject, e.g., a human, or a non-human animal, and evaluating the level of PKC activity, e.g., PKC xcex2 activity, in the subject""s monocytes.
In a preferred embodiment, PKCxcex2 activity is evaluated.
In a preferred embodiment, the subject is a human.
In a preferred embodiment, the subject is an experimental animal.
The methods described herein can be used, e.g., to evaluate the effect of a treatment on PKC activity before, during, and/or after administration of a treatment. In some embodiments, the effect of a treatment can be evaluated over time (e.g., over minutes, hours, days, weeks, months) by repeating the evaluation of PKC activity as described herein. For example, PKC activity can be evaluated one, two, three, four, five, or more times after the initial evaluation of PKC activity in response to treatment. In other embodiments, the treatment can be administered more than once, and the effect of subsequent administrations can be evaluated by repeating the evaluation of PKC activity in mononuclear cells, e.g., monocytes, as described herein.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.